Add a few missing overrides found by a new clang warning.

win8/metro_driver/ime/text_service.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "win8/metro_driver/ime/text_service.h"
 
 #include <msctf.h>
 
 #include "base/logging.h"
 #include "base/win/scoped_variant.h"
@@ skipping 374 matching lines @@
                                     selection_end,
                                     underlines);
   }
 
   virtual void OnTextCommitted(const base::string16& text) override {
     if (!delegate_)
       return;
     delegate_->OnTextCommitted(text);
   }
 
-  virtual RECT GetCaretBounds() {
+  virtual RECT GetCaretBounds() override {
     if (composition_character_bounds_.empty()) {
       const RECT rect = {};
       return rect;
     }
     const metro_viewer::CharacterBounds& bounds =
         composition_character_bounds_[0];
     POINT left_top = { bounds.left, bounds.top };
     POINT right_bottom = { bounds.right, bounds.bottom };
     ClientToScreen(window_handle_, &left_top);
     ClientToScreen(window_handle_, &right_bottom);
@@ skipping 78 matching lines @@
     thread_manager->Deactivate();
     return scoped_ptr<TextService>();
   }
   return scoped_ptr<TextService>(new TextServiceImpl(thread_manager,
                                                      client_id,
                                                      window_handle,
                                                      delegate));
 }
 
 }  // namespace metro_driver